Midterm 2 Flashcards
NMJ prep and ACh causes what?
EPP (or measure EPC with voltage clamp
Is there current flow at Erev?
No current flows at reversal potential.
What can you use Erev for?
See which ions are flowing.
Current reverses direction at _____ mV for ACh channels.
0mV. Open to both Na+ and K+ions.
What drives PSP or EPP and towards what?
Neurotransmitters drive the PSP or EPP towards Erev for the ion(s) that flows.
Large EPPs ensure what?
Generation of an AP is propagated in a muscle cell.
Are PSPs bigger or smaller than EPPs?
Much smaller (fractions of mV) than EPPs and are rarely sufficient to generate an AP.
Post-synaptic cell sums what?
EPSPs and IPSPs
PSPs are depolarizing if …
Erev is more POSITIVE than the resting membrane potential (always the case for EPPs).
PSPs are hyperpolarizing if …
Erev is more NEGATIVE than the resting membrane potential of the post-sypnatic cell.
If the Erev for a PSP is more positive than the resting membrane potential, a neurotransmitter is …
Excitatory and an EPSP is generated. If EPSP is above AP threshold, AP is generated.
If the Erev for a PSP is more negative than the AP threshold, then the neurotransmitter is …
Inhibitory and an IPSP is generated (either with a hyperpolarizing or a depolarizing current).
Where is ACh found?
- NMJ
- ANS
- CNS basal forebrain (Alzheimer’s)
What is the main function of glutamate?
- Major excitatory neurotransmitter.
2. Amino acid
What is the main function of GABA?
- Main inhibitory neurotransmitter
2. Amino acid
Where is Gly important and its function?
Important amino acid in the spinal cord synthesized from Serine and is an inhibitory NT.
Where is Dopamine found?
- Substantia Nigra (control of movement)
- VTA (reward pathway to NAc(nucleus accumbens)) only 100,000 DA neurons.
- Biogenic amine
Where is noradrenalin found?
- Source: locus coeruleus in sympathetic neurons.
2. Biogenic amine
Where is adrenalin found?
- Few cells in medulla, hormone releases from adrenals.
2. Biogenic amine
Where is Dopamine found?
- Substantia Nigra (control of movement)
- VTA (reward pathway to NAc) only 100,000 DA neurons.
- Biogenic amine
Where is noradrenalin found?
- Source locus coeruleus in sympathetic neurons.
2. Biogenic amine
Where is adrenalin found?
- Few cells in meuall, hormone releases from adrenals.
2. Biogenic amine
Where is indoleamine - serotonin found?
- Raphe nuclei
2. Biogenic amine
Where is histamine found?
Hypothalamus
2. Biogenic amine
Which purine can be used as a NT?
ATP (from adenosine), important in taste: sweet, bitter, and umami.
What are opioids for?
- Endogenous analgesia
2. Neuropeptide
What are neuropeptides in the hypothalamus and pituitary used for?
- Homeostasis control: weight, sleep, growth, sex, etc).
What are three unconventional neurotransmitters?
- Endocannabinoids
- NO
- Adenosine
What are the two types of ACh receptors?
- Ionotropic (nAChR)
2. Metabotropic (mAChR)
What 3 receptors does Glutamate use?
- Ionotropic (mainly AMPA - rapid, large ion flow)
- NMDA (co-incident detector: need depolarization usually from AMPA)
- LTP: Kainate (mGluR)
What receptors does GABA use?
- Ionotropic (Cl- ions flow - bind benzodiazepines, barbiturates, alcohol, and metabotropic)
What receptor(s) does Dopamine use?
Metabotropic only
What receptor(s) does Noradrenalin use?
Metabotropic
What receptor(s) does serotonin use?
- Ionotropic (anti-nausea)
2. Metabotropic
What receptor(s) does ATP use?
- Ionotropic
2. Metabotropic
What receptor does adenosine use?
Metabotropic
Where is ACh terminated?
AChEsterase in synaptic cleft
Where are amino acids terminated?
Transported into glia and neurons
Where are monoamines terminated?
Transport (re-uptake) into pre-synaptic terminals.
- MAO and COMT in pre-synaptic terminal (degrade DA, NE, Ep)
Where are purines terminated?
ATP into adenosine in synaptic cleft
Where are neuropeptides terminated?
Proteases in synaptic cleft
Examples of NMDA antagonists and what NT receptor it acts on.
- Anesthetics (e.g. Ketamine)
2. Act on Glutamate. (mGluRs)
What do benzodiazepines do?
- Enhance GABA action
- EG Diazepam
- Anti-convulsant
- Muscle relaxant
What do barbiturates do?
- Open GABA channel longer
- Used as anesthesia
- Anti-convulsant (hypnotics)
What does picrotoxin do?
- Block GABA channels (used in lab, causes seizures).
What does valproate do?
- Blocks GABA transanimase in epilepsy, bipolar.
What is MAOi?
- MAO inhibitor.
2. EG phenelzine = Anti-depressant
What are tricyclics?
- Anti-depressant
2. Block reuptake of NE
What does prozac do?
- aka SSRI
- aka Fluoxetine
- Inhibits reuptake of Serotonin.
- Anti-depressant, OCD, panic disorder
What do amphetamines do?
- Release of DA, NE, 5-HT (high doses)
- Also DA and NE reuptake inhibition
- Used for ADHD (Ritalin), chronic fatigue syndrome, and narcolepsy.
What does cocaine do?
- Blocks reuptake of DA
What does methamphetamine do?
- Release of DA, NE, 5-HT (even more than amphetamine).
2. DA and NE reuptake inhibition.
What does MDMA (ecstasy) do?
- Serontonin release
- Reuptake inhibition
- Lesser effects on DA and NE reuptake
What does Caffeine do?
- Affects purines
- Theophylline block adenosine receptors
- Ryanodine agonist
- PDE inhibitor
What do opiates do?
- Neuropeptides that act as analgesics (heroin, morphine, codeine, oxy)
- Act as agonists at opioid receptors
What does phosphadisterase do?
Inactivates cAMP and cGMP.